Arcuate piston



R. L. SNYDER ARGUATE PISTON Dec. 31, 1946.

Original Filed Aug. 5, 1943 2 SheetsSheet 1 GHQ-neg 13%.31, 1946.LSNYDER 2,413,590

ARCUATE PISTON v Original Filed Aug. 5, 1945 2 Sheets-Sheet 2 BLGWE/EInventor fi'ziilanil.5rgder Z. W

Gltorneg Patented Dec. 31, 1946 ARCUATE PISTON Richard L. Snyder,Glassboro, N. J., assignor of one-fourth to Henrietta B. Snyder,Glassboro, one-fourth to Richard L. Snyder, Jr., Princeton, andone-fourth to Christopher L. Snyder,

Metuchen, N. J.

Original application August 5, 1943, Serial No. 497,420. Divided andthis application March 27, 1945, Serial No. 585,139

2 Claims.

This application is a division of my copending U. S. application, SerialNo. 497,420, filed August 5, 1943, entitled Internal combustion engines.

This invention relates generally to internal combustion engines and moreparticularly to valveless internal combustion engines having at leastone continuous toroidal cylinder cavity including therein at least onepair of double ended arcuate pistons disposed in mutually cooperativerotary reciprocative relation.

The preferred embodiment of the invention to be described in detailhereinafter utilizes relative reciprocative motion of double endedpistons combined with absolute rotary motion of said pistons fortransmitting rotary motion to a drive shaft. Power is transmittedthrough a translating system, comprising connecting rods journaled tosaid pistons and to a conventional crank shaft, and crank means securedto the drive shaft and journaled to said crank shaft. In operation, eachcylinder comprises the space intermediate adjacent ends of any two ofthe double-ended pistons within the continuous toroidal cylinder cavity.An explosive mixture is introduced into the space intermediate the endsof each of the two pistons progressing past one or more fixed valvelessintake ports, the mixture is then subjected to compression, and thecompressed mixture is next subjected to an ignition device whichexplodes the compressed gas. The exploded mixture delivers power whichdrives the particular pair of pistons in relative opposite directions,thereby providing reciprocative piston motion with resultant rotarymotion of the drive shaft. 'As the rotary reciprocative motion of thepistons again moves the adjacent faces thereof toward each other, therotary motion of the pistons brings the space intermediate said pistonsadjacent one or more fixed tion is to provide a counterbalanceddouble-ended arcuate piston having a plurality of piston rings fittedthereto, and arranged to rotate within a continuous toroidal cylindercavity.

The invention will be described in further detail by reference to theaccompanying drawing of which Figure 1 is a cross-sectional elevationalview of one embodiment thereof taken along the section lines I, I, ofFigure 2 which is a cross-sectional view of. the same embodiment takenalong the section line 11, II of Figure 1;

Figure 3 is an enlarged fragmentary cross-sectional view of a portion ofthe cylinder cavity showing the ring bearing-gas seal.

Similar reference characters are applied to similar elements throughoutthe drawings in order to illustrate better and simplify the accompanyingdescription thereof.

Referring to Figures 1 and 2, the preferred embodiment of the inventionis shown as a component of a four-stroke-cycle engine having meansdefining a single toroidal cylinder cavity having four pistons disposedtherein. The means defining the toroidal cylinder cavity comprise afirst split casting portion I having a keyed portion which engages acomplementary keyway in a second split casting portion 2. The twocasting portions l, 2 are clamped together by means of bolts which passthrough coincidental apertures 3 equispaced around the peripheral edgesof the circular complementary casting faces adjacent the keyed portionsthereof. The castings I, 2 include cut-out portions for providing awater jacket for cooling the cylinder cavity walls. The castings alsoinclude intake and exhaust apertures 4, 5, respectively, which areconnected to suitable intake and exhaust manifolds 6, I, respectively.

The opposite ends of the castings l, 2 each are journaled to a maindrive shaft 8. Fixed gears 9, H! are adj'ustably secured to opposite endportions of the castings l, 2, respectively. Adjustment of the angularposition of the gears 9, H1 is provided by a radially extending arm H,secured to both of the gears. The gears may be clamped in anypredetermined angular position by means of clamping bolts l 2 havingexternal wing nuts l3. The bolts extend through the gears 9, l0 andthrough slots in the adjacent end portions of the casting l, 2.

A spark plug, or glow plug, l4 extends into a spark plug port,proportioned therefor, which opens into the cylinder cavity. Connectionsfor the spark plug M are made to a high tension ignition coil I5. Abattery. or other source of ignition potential I6, is connected to theprimary circuit of the ignition coil l5 through a conventio ignitioncontactor ll which is operated by a earn it. The cam i8 may be mountedon one end of the drive shaft 8, or may be actuated in any other knownmanner. If a glow plug is used, it may be energized continuously fromthe battery it, and ignition timing provided by piston position.

The drive shaft 8 extends centrally through the castings I, 2 normal tothe plane of the cylinder cavity. An external flywheel l9 may, ifdesired, be secured to the opposite end of the drive shaft from theignition cam H3. The flywheel i9 may include gear teeth 20 for drivingaload, and for cooperation with a starter motor of conventional type.

Four pistons 2|, 22, 23, 24 are disposed within the cylinder cavity.These pistons are arcuate in shape and double-ended to provide fourcylinders intermediate each two adjacent piston faces. The pistonsinclude conventional .piston rings 25 and-a novel counterbalancearrangement for minimizing radial thrust between the peripheral faces ofthe pistons and the interior of the cylinder cavity. The pistons 2|, 22,23, 24 are pivoted on corresponding main connecting rods 26, H, 28, 29,respectively, which as illustrated comprise a pair of double-ended rodseach floated upon the main drive shaft 8.

Considering the piston 2 l, for example, the piston casting includesrotatable bearings 3|), 3| in which a piston pin 32 is journaledeccentrically. A. counterweight 33, is secured to the rotatable bearings39, 3|. One end of the corresponding main connecting rod 26 is journaledto the center portion of the piston pin 32 intermediate the internalends of the piston bearings 30, 3|. It will be seen that normal radialthrust of the piston due to rotation thereof within the cylinder cavitywill be compensated for by means of the resultant radial thrust of thecounterbalance 33. Radial thrust of the counterbalance 33 will rotatethe piston bearings 38, 3| counterclockwise, thereby increasing theradial thrust of the piston pin 32 in its bearing in the end of the con-A gas seal for the inner peripheral slot comprises a split-ring hearingwhich extends into the slot and includes apertures having flexible facesfor receiving the corresponding connecting rods. The split ring bearingsinclude two separate sets of ball'bearings H, l2 which contact racewayson the sides of a cylinder slot. The two portions '13, M of the cylinderbearing are adapted to reciprocate with respect to each other while atthe same time providing an effective gas seal between the reciprocatingportions and around the sides having the ball bearings in contact withthe cylinder cavity bearing raceways.

As explained. heretofore, thefour pistons 2 I, 22,.

25, respectively, are pivoted on corresponding main connecting rods.v26, 21 2d, 29, respectively.

The first andth-ird connecting rods 26, 28 may comprise a unitary orrigid structure which is journaled on the main drive shaft 8. Similarly,the second and fourth connecting rods 21, 29 may comprise a secondunitary or rigid structure also journaled on the main drive shaft 3adjacent the first and third connecting rods. A pair of cocentric crankshafts 34, 35 are interposed be tween the inner peripheral limits of thecylinder cavity and the main drive shaft 8. The axial portions of thefirst and second crank shafts 34, 35, respectively terminate at theirends in pinion gears 35, 3? which engage respectively the fixed gearsHi, 9, respectively. The eccentric portions of the crank shafts 34, 35,respectively,'are each journaled to receive two auxiliary connectingrods which, in turn,-are journaled to adjacent main connecting rods.

For example, the first eccentric crank shaft 34 is journaled to a firstauxiliary connecting rod 38 which, in turn, is journaled to the firstmain connecting rod 26. Likewise, a second eccentric portion of thefirst eccentric crank shaft 34% is journaled to a second auxiliaryconnecting rod39 which is journaled to the fourth main connecting rod29, The wrist pin for the first main connecting rod 23, as shown inFigure 1, is held in a bracket 48 secured by bolts 4| to the side of themain connecting rod. The bracket to terminates in a forked portion 42which receives the first auxiliary connecting rod 38 and which ispivoted thereto by means of a wrist pin 43. The second, third and fourthmain connecting rods are similarly journaled to corresponding auxiliaryconnecting rods which, in turn, are journaled to either the first orsecond eccentric crank shafts 34, 35 as explained heretofore. As amatter of convenience, both the main and auxiliary connecting rodbearings may be of the conventional split bearing type to facilitateassembly and replacement thereof. Similarly, other bearings describedherein may be-of the split type for the same reason.

The axial portions of the first and second crank shafts 34, 35 are alsojournaled in cylindrical cranks 44, 45 which are disposed intermediatethe main connecting rod bearings and the fixed gears 9, i ii. The twocylindrical cranks 4 3, 45 are both keyed by means of keys 4B, 47,respectively, to the main drive shaft 8.

It will be seen that relative reciprooative motion of the four pistons 2I, 22, 23, 24 will provide similar reciprocative motion of thecorresponding main connecting rods 26, 28 with respect to the remainingpair of connecting rods 21, 29. Considering only the main connectingrods 26, 29; relative reciprocative motion thereof will provide rotarymotion of the first crank shaft 34 due to the coupling provided betweenthe main connecting rod and the eccentric crank shaft by means of theauxiliary connecting rods 38, 39, respectively. Since the rotary motiondelivered to the eccentric crank shaft 34 will be transmitted-to thecorresponding pinion gears secured to the axial ends thereof, the piniongear will rotate about the fixed gears 9, Hi. The rotation of the piniongears about the fixed gears will thereby provide rotary motion of thecylindrical cranks 44, 45 keyed to the main drive shaft 8, and of the ofthe mainconnecting rods 25, 29 coupled thereto.- Since the first andfourth main connecting rods 26., '29, and the thirdand secondconnecting.

rods 28;, 27 rigidly coupled respectively thereto,

are caused to rotate about the axis of the main drive shaft 8, thecorresponding pistons 2|, 22,

23, 24 will also rotate about the axis of the center shaft 8. Ittherefore will be seen that the pistons have relative reciprocativemotion with respect to each other-and, in addition, have rotary motionalong the toroidal cylinder cavity due to the travel of the pinion gearsaround the complementary fixed gears secured to the cavity structure.

Similarly, the ring bearings providing the gas seal within the slottedinner periphery of the cylfinder cavity will rotate as the correspondingconnecting rods passing therethrough rotate about the. main drive shaft8. Also, the two portions of the split bearing-gas seal will reciprocatewith respect to each other in the same manner and at the same time asthe adjacent connecting rods and pistons reciprocate with respect toeach other.

The locations of the intake and exhaust ports 4, 5, respectively, withrespect to the location of the ignition plug Hi, are clearly illustratedin Figure 2. If we consider a typical four-strokecycle insofar as thecylinder intermediate the third and fourth pistons 23, 24 is concerned,clockwise rotation of the pistons, as indicated by the arrow, willprovide gas intake to the cylinder from the intake manifold ii throughthe intake ports l, since in this position the third and fourth pistons23, 26, respectively, are moving away from each other. As the clockwiserotation of the pistons progresses, the pistons commence to move towardeach other, due to the reciprocative motion thereof, and at a pointsubstantially coincidental with the ignition plug E4 the com-- pressionof the explosive mixture between the pistons reaches a maximum value,The ignition provided by the ignition device 84 explodes the compressedgases, delivering power to the pistons tends to drive them fartherapart, thereby delivering energy to the corresponding main connectingrods 28, 29. When the pistons 23, 2 1, reach a position approximatelycoincidental with the illustrated position of the piston 22, as shown inFigure 2, they commence to move toward each other again, therebyproviding pressure for exhaustion of the exploded gases through theexhaust ports 5 and the exhaust manifold 7. After the cylinder haspassed, the exhaust ports 5, the pistons 23, 2:! again begin to moveapartand pass the intake ports 4 for a repetition of thefour-stroke-cycle thus described.

If desired, a scavenging blower 50 may be connected to one or more ofthe exhaust ports to facilitate scavenging of the cylinder during theexhaust stroke. Any conventional type of carburetor 5l' and intakemanifold connection 52 may be provided which will furnish a suitableexplosive mixture to the intake ports 5. Similarly, forced intake of theexplosive gaseous mixture may be provided by applying pressure to forcethe mixture from the carburetor through the intake ports 4 when they areuncovered by the several pistons.

It will be seen that the cylinder intermediate each pair of double-endedpistons will follow the same four-stroke-cycle as that describedheretofore, and that a single set of intake ports, exhaust ports and asingle ignition plug will provide similar operation for each of thesuccessive cylinders passing these points. Therefore, it will be seenthat each complete revolution of a particular piston about the maindrive shaft 8 will occur during four complete four-stroke-cycles of thecylinders intermediate the various pistons. Since the gear ratio betweenthe pinion gears 36, 3'! and the fixed gears l9, 9 respectively, areselected to be of one to two ratio, the main drive shaft will be turnedby the cylindrical cranks 44, 45, through one complete revolution aseach of the pistons turn through one complete revolution, therebyproviding four explosions of the gaseous mixture for each completerevolution of the main drive shaft.

The external flywheel l9 may, if desired, be omitted, since considerableinertia is provided by the relatively heavy cylindrical cranks 44, whichare keyed to the main drive shaft 8.

Oiling of the various bearings and moving surfaces described heretoforeis provided by a central oil pump 54 of conventional design. The oilunder pressure from the pump 54 is introduced, for example, into the endof the main casting i and passes therethrough through an oil duct 55,The bearing 55 in the end of the main casting l includes a slottedportion 51 which coincides with a hole 58 extending into the main driveshaft 8. The hole 58 terminates in a longitudinal hole 59 which extendssubstantially the full length of the main drive shaft 8. Radial holes,connecting the interior hole 59 of the main drive shaft to the peripherythereof, are

provided at each of the bearings 56, 6| of the main connecting rods. Themain connecting rod bearings Gil, 6! each include slotted portions 62,63, respectively, which connect to radial oil ducts 55, within thecorresponding main connecting rods. The radial oil duct 64 in the mainconnecting rod 26 extends the full length thereof to supply oil to thepiston pin 32 of the piston 2|. The wrist pins 43, between the auxiliaryconnecting rods and the forked bracket bearings 42, are lubricatedthrough the duct 65 in the cylindrical crank 44 and the longitudinalduct 66 in the crank shaft 35, and thence through longitudinal ducts inthe auxiliary rods. Similarly, a portion of the oil circulating throughthe radial duct E l is diverted within the piston 2| to lubricate thesurface faces thereof adjacent the piston rings 25. Lubrication for theeccentric crank shaft bearings is provided by a radial duct 65 extendingthrough the cylindrical crank 44 to the axial portion of the eccentriccrank shaft 35 journaled thereto, as explained heretofore with respectto the wrist pins. Lubrication for the bearing in the end of theauxiliary connecting rods journaled on the eccentric portion of thecrank shaft is provided by a longitudinal oil duct 86 through the centerof the eccentric crank shaft.

Figure 3 shows, in cross-section, the double sealing rings 13, M, whichprovide a gas seal for the slot on theinner peripheral surface of thetoroidal cylinder cavity. Each of the rings are apertured to receivedifierent ones of the several main connecting rods, as shown in Fig. 1.The sealing rings include polished complementary surfaces i5, 'e whichprovide a satisfactory gas seal for the cylinder cavity while permittingrelative reciprocative motion of the two rings. The sealing rings arearranged to revolve with respect to the cylinder cavity as the mainconnecting rods which pass therethrough revolve about the main driveshaft 8. The sealing rings are accurately centered adjacent the cylindercavity slot by means of the ball or roller bearings ll, 12 disposed inbearing guide channels TI, 18. One sealing ring M is split and isprovided with an expanding spring member 19 disposed intermediate thesealing ring and the split ring portion 80. The expanding spring memberis mor- 7 tised'to-the main portion of. the sealing ring HI in anyconvenient manner to prevent substantial gas leakage. The continuouspressure provided by the spring member 79 provides uniform contactbetween the complementary surfaces of the reciprocating sealing rings,and also constitutes a simple and effective means for compensating forincidental wear of either of the reciprocating rings, or the cylindercavity guides therefor. Additional springs 8|, 82 are interposed inslots in the cavity wall to exert pressure on the bearing portions it,till, respectively. The split sealing ring is preferably constructed sothat internal pressure aids the spring member H to improve the gas seal.

It should be understood that these reciprocating sealing rings may beemployed to provide the actual power transmission means between therotary reciprocating pistons and the eccentric crank shafts. It will beseen that the ball bearing arrangement for floating the sealing ringsupon the inner peripheral wall of the cylinder cavity provides a bearingsurface which effectively prevents radial thrust of short connecting rodmembers which may be provided to connect the individual pistons tocorresponding ones of the sealing rings. This arrangement saves thespace ordinarily required for the main connecting rods which, as shownin Figs. land 2, are journaled to the main drive shaft, and therebypermits relatively heavier main drive shafts and eccentric crank shaftsto be employed in engines of predetermined cross-sectional dimensions.

Thus the invention disclosed herein comprises a toroidal type internalcombustion engine including one or more toroidal cylinder cavities eachhaving a plurality of arcuate double-ended pistons disposed therein inmutual rotary reciprocative relation. A novel piston counterbalancingarrangement reduces cylinder and piston wear.

I claim as my invention:

1. A counterbalanced piston for a rotary engine comprising adouble-ended arcuate piston shell portion, a pair of eccentricallyapertured bearings having their outer surfaces journalled in said shellportion, at least one counterweight pivoted on said outer surfaces ofsaid bearings and disposed to rotate with said bearings within saidshell portion, a piston pin journalled in said eccentric bearingapertures, and journal means for connecting said piston pin to anexternal utilization device.

2. A counterbalanced piston for a rotary engine comprising adouble-ended arcuate piston shell portion, piston rings on the peripheryof said shell portion, a pair of eccentrically apertured bearings havingtheir outer surfaces journalled in diametrically opposite sides of saidshell portion, at least one counterweight disposed within said shellportion and pivoted to rotate with said diametrically disposed bearings,a piston pin journalled in said eccentric bearing apertures, and meansfor connecting said piston pin to an external utilization device.

RICHARD L. SNYDER.

